Neuralgia is often nothing more than a form of nervous gout or rheumatism, in which cases the opiate may be associated with the wine or extract of colchicum, and frequently also advantageously with a saline cathartic.

Nervous headache, or sick-headache, will often yield happily to a full dose of opium or morphia, which is most effectual, however, in the latter affection, when it perseveres, after evacuation of the stomach. But care must be taken not to confound this complaint with headache from vascular irritation, or active congestion of the brain.

In cancerous affections it is often necessary to have recourse to anodynes; and the observations above made, in relation to the precautions necessary to guard against the abuse of the medicine in incurable neuralgia, and to obtain the greatest amount of good from it, are equally applicable to this ease.

The same remark may be made of aneurisms and all other tumours. which, though not painful in themselves, often become extremely so by pressure on the trunks of neighbouring nerves, or in other modes interfering with the healthy structure near them.

Painful spasms afford still stronger indications for the use of opium than simple neuralgia, because often more dangerous in their consequences, and because, also, being only occasional, and generally occurring at distant intervals, there is less danger of an abuse of the remedy. These spasms may be either external, affecting the voluntary muscles, or internal, affecting the muscles of organic life. Of the former we have examples in ordinary cramps of the limbs, in the intensely painful cramps of cholera, and in tetanus. It is in the two latter affections chiefly that opium is used; and in both it is certainly among the most efficient remedies. In tetanus, the insusceptibility of the cerebral centres is such, that much larger doses are required than under ordinary circumstances. Two grains may be given at first every two hours, and, if necessary to bring about relief, the dose may be increased to four, five, or six grains, or an equivalent proportion of morphia or one of the liquid preparations, repeated as often, until some degree of narcotic effect is experienced; but the quantity of half a drachm of opium in twelve hours should in no case, I think, be exceeded; as, if the disease should suddenly give way, poisonous effects might ensue from the portion remaining unabsorbed in the stomach. The internal painful spasms are those of the stomach, of the bowels in the different forms of colic, of the ureters and ducts of the liver from the passage of calculi, of the bladder, of the uterus, and finally of the diaphragm and the heart. In all these affections the pain is often exquisitely severe, and in some of them life is endangered by the continuance of the spasm. All of them afford the clearest indications for the use of opium, which may in general be given unhesitatingly, and in quantities requisite to obtain relief, beginning with a full dose, and increasing until the pain is alleviated, or narcotic effects induced. The same insusceptibility to the influence of the anodyne exists as in tetanus, though usually in a much less degree; and it is seldom necessary to exceed two grains of opium, or an equivalent quantity of its preparations, at one dose. The liquid preparations are preferable to solid opium, as they operate more speedily. In these several affections, it is necessary to combine special modes of treatment with the anodyne, which, however, this is not the proper place to detail. As examples, it may be mentioned that, in gouty spasm of the stomach, colchicum may be combined with the opiate; in ordinary colic, castor oil; in bilious colic, calomel; in spasm of the heart or diaphragm, ether or chloroform; in spasm of the hepatic duets, ether and oil of turpentine; in that of the ureters, the alkaline bicarbonates; that in all of them sinapisms and the warm bath are efficient adjuvants; and that, when not contraindicated by debility, the lancet may often be used with powerful effect in producing relaxation. The spasmodic pain attending enteritis, cholera, dysentery, and peritonitis, affords an indication for the use of opium; but those founded on other effects than the merely anodyne are much more important.

Various spasmodic and convulsive affections, not painful in their character, or but slightly so, belong to the category of nervous irritations, and are more or less benefited by opium. Such is the paroxysm of spasmodic asthma, in which opium will often afford relief, though it is liable to the objection of checking bronchial secretion, and is, on the whole, much less efficient than some other narcotics and nervous stimulants or sedatives. In epilepsy it may sometimes be used as a palliative; but, on the whole, is better avoided, both from its liability to abuse, and from its congestive influence on the brain. In hooping-cough it is liable to the same objection as in asthma, and should be used only as a palliative of the cough, in connection with expectorants. To chorea it is scarcely appropriate, unless to obviate occasional intercurrent affections. In the various spasmodic affections of hysteria it is for a time an almost sovereign remedy; but, on moral grounds, requires to be prescribed with caution. In the convulsions of infants, depending on intestinal spasm, opium is an excellent adjuvant of other remedies.

To the list of nervous irritations relieved by opium may be added obstinate wakefulness, general uneasiness, restlessness, languor and faintness, palpitations, nervous cough, and all the protean derangements of hysteria; but, as a general rule, it is better to seek relief, in these affections, when not associated with other serious diseases, from remedies less accordant with the propensities of our nature, and less liable to abuse.